Rapid and accurate methods are needed to detect agents which might be used in a bioterrorist attack, particularly “Category A” agents. Category A agents, as defined by the U.S. Centers for Disease Control and Prevention (CDC), include organisms that pose a public health risk because they can be easily disseminated or transmitted from person to person and that result in high mortality rates. Smallpox, a Category A agent, is considered to be a particularly dangerous threat, as fatality rates could be higher than 25% from exposure to the smallpox virus.
Earlier methods for detecting DNA viruses like the smallpox virus involve the time-consuming process of growing viable virus particles from a sample potentially containing the virus. More recent PCR- or antibody-based methods are potentially very rapid and sensitive, and can possibly be incorporated into portable devices. However, it is necessary to know enough about the viral agent of interest to design appropriate primers or to generate an antibody in order to use such methods. This means that a viral agent could be genetically engineered, or could naturally mutate, such that its genome or proteins would not be detected by these methods. In addition, PCR- and antibody-based assays do not distinguish between viable, infectious agents and non-viable or inactivated agents.